At least in the UK if you've lived here (under whatever visa or rules allow you to) for 10 years and pass some fairly straightforward (if a bit silly) tests you

At least in the UK if you've lived here (under whatever visa or rules allow you to) for 10 years and pass some fairly straightforward (if a bit silly) tests you can effectively stay indefinitely (whether you aim to become a full citizen or not). The process is a bit expensive and bureaucratic (and the home office often maliciously incompetent), but in principle if you've stayed here long enough you don't have much threat of being kicked out.